Thomas & Charlotte Mountain buried in Alpena, SD

Thomas & Charlotte Mountain buried in Alpena, SD

My gr-gr-grandparents Thomas (b c 1810) & Charlotte (b c 1815) Mountain are apparently buried in Rest Haven Cemetery, Alpena, Jerauld Co, South Dakota, USA. Their deaths occurred between 1890 and 1900. Can anybody find their death dates? They were probably living with their daughter and son-in-law, Charlotte (1856-1951) and John H Buell (1858-1948), who farmed in Alpena. Thanks.